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What is Double Glazing?
Double glazing refers to a window having double-glazed units. The double-glazed unit consists of two panes of glass with a space between them. Technical experts refer to this space as a cavity.
This cavity usually comprises inner gases like krypton and argon. Why is this gas important? The gas works like an insulative barrier. As an insulative barrier, it helps reduce heat transmission levels and the energy bill.
This window type has a wide range of customization options. For instance, the double-glazed unit’s composition (10/8/4, 4/1/4, or 4/8/4) or it has a solar control/ low-E glass coating/ sound insulation layer.
Vacuum double glazing
Vacuum-sealed is another popular type of double glazing that’s common in historic building restoration projects. How is this type different from the standard double-glazed units? The differentiating factor is that the vacuum double glazing’s cavity has a vacuum inside.
Studies show that the vacuum transmits fewer amounts of thermal energy than inner glasses. This property makes it superior in insulation needs and helps to reduce heating bills.
The vacuum’s technical characteristics make the cavity between the two panes thinners (approximately 1 mm). Despite the narrow distance, it doesn’t affect the thermal properties. Thus, you can now get slim double glazing you can use in projects like sash window retrofitting. In contrast, you can replace single glazing in the original wooden sash windows with heritage double glazing. You can achieve this without changing the window sashes or frame.
Most individuals consider this double-glazing type a breakthrough. It’s a breakthrough as it helps keep the old historic properties more energy-efficient, and you won’t need to change the original window frame.
The latest developments in this vacuum double glazing have made these changes possible. Remember, these developments and changes weren’t available a decade ago. With these developments and properties, vacuum double glazing has become an ideal choice when having original wooden frame windows.
Low-emissivity and laminated glass
Studies show that there are a few other glass technologies individuals use for modern double-glazed units, for instance, low-emissivity glass. What is low-emissivity glass? It’s a special type of glass with a coating on its glass panes. The coating helps to reduce the heat transmission levels through the glass.
Experts also refer to it as heat-reflective or smart glass. You can also refer to the coating as Low-E glass. The uniqueness of the glass makes it vital in the constituents of double glazing. Experts use it in the composition to improve the window’s solar control properties and energy efficiency.
Lamination glass is also another popular type of safety glass. Manufacturers make the glass by bonding two glass sheets together with a layer of a given plastic in between. You can use this glass in double glazing. It helps improve the security of the windows and reduce unnecessary noise.
Single-glazing Drawbacks
Experts reveal that the main drawback of single glazing is the limited insulation they offer. These windows may let in huge amounts of cold air in the winter, making it hard to warm your house. This situation reverses in the summer, as the windows make your home extra hot and unbearable.
Thermal Efficiency
Regarding energy efficiency and insulation, single glazing has a slightly lower performance. Single glazing has a high energy transmission rate. The high transmission rate results in the easy transfer of heat from one extreme to another. During winter, it allows cold temperatures to penetrate the interior, necessitating increased heating to offset this impact.
Single glazing typically consists of a single sheet of glass. A single glass sheet is usually 4 to 6 mm thick or even thicker. It’s similar to holding a cup of boiling water, as it easily transfers heat. In contrast, double glazing acts like a thermos.
Just like how you don’t feel the heat when holding a thermos having hot water, double glazing uses layers and insulation to prevent heat from easily escaping or entering through the window.
Reduce and Insulate Against Noise
Besides having poor thermal insulation, single-glazed windows also provide limited noise reduction.
Thus, if you reside near a construction site on a busy street, the noise can be excessive and have a negative impact on your well-being.
In contrast, double-glazed windows can help minimize the amount of noise entering your home. However, the effectiveness of soundproofing varies based on the double glazing’s quality and composition.
Insufficient Security
Single glazing is more vulnerable to breakage than double glazing because it consists of a single pane of glass. This compromises your home’s security against burglars, particularly for ground-floor windows.
If you reside in an area prone to crime, your property is at an increased risk. However, using toughened double-glazing units helps to enhance the security of your house.
Condensation Is a Problem With Single-Pane Windows
Single-glazed windows are prone to generating condensation on the inside of the glass pane. The increased condensation occurs due to their high energy transmission level.
How does it happen? Condensation forms when warm indoor air meets a single glass sheet’s cold surface. This process leads to potential issues with mould and mildew inside the house. These problems can pose significant health risks if left unaddressed, particularly during winter when temperature differences are pronounced.
Retrofitting double-glazed units into your current window frames is an effective solution. How do these units help? They possess superior thermal properties that prevent condensation buildup on the inner window pane.
Reasons to Double Glaze Your Home’s Single-Glazed Windows
Despite the benefits and drawbacks of double-glazing, single-glazed windows remain prevalent in homes and commercial properties across the UK. This is especially true in regions like East Anglia and the South East. Grade 2 listed properties (with over 80,000) houses in East Anglia and more than 14,000 houses in Essex often still have single-glazed windows. However, even non-listed houses with single glazing can reap the advantages of double glazing.
What Should I Do When Living in Grade 2 Listed Home?
If you reside in a conservation area or listed building with original wooden windows, replacing them can be costly. You may also not receive approval from local conservation officers. Retrofitting double glazing becomes the practical choice in such situations.
The primary motivation for transitioning to double glazing is the rising energy costs and the desire for enhanced comfort at a lower expense. Our sash window double-glazing service caters to homeowners or individuals having single-glazed timber frame windows. Contact us for a quote or visit our pricing page for cost information.
Please note that we exclusively specialize in retrofitting double glazing for original timber frame windows. So, we do not work with UPVC or aluminium frames. As a double-glazing company, we only offer services associated with sash window double-glazing retrofitting.
U-Value of Different Types of Window Glazing
| Type | U-value |
| Single glazing | 5 – 5.8 |
| Triple glazing | 0.6 – 1 |
| Double glazing | 1.2 – 2.2 |
| Vacuum double glazing | 0.54 – 0.7 |
Options for Double Glazing
If you’re seeking alternative methods for insulating your single-glazed windows and minimizing noise and heat transfer, consider secondary glazing as a viable option. Unlike retrofitting or replacing with double glazing, this alternative involves installing an additional layer of glazing on the interior of different window types, such as sash windows.
While not as energy-efficient as double glazing and less visually appealing, it can still improve your home’s comfort.
Energy Efficiency of Single-Glazed Windows
When searching for new double-glazed windows or obtaining quotes for secondary glazing, it’s crucial to assess the window’s energy rating. Why is it important to assess this rating? This rating serves as a reliable indicator of the amount of heat the window loses. Higher energy ratings signify better insulation and reduced heat loss.
Studies show that A-rated windows are the best energy-efficient alternatives. In contrast, G-rated windows offer the least energy-efficient properties, with single-glazed windows falling into the G-rated category.
However, it’s important to note that insufficient insulation is not solely attributed to single glazing. Factors such as proper window installation, window frame material, and insulated walls also significantly impact a house’s overall insulation and energy performance.
Final Thoughts
Single-glazed windows come with both pros and cons. The primary advantage is their affordability, making them cheaper than double or triple glazing. However, the main drawback lies in their inadequate energy efficiency. The inadequate energy efficiency results in heat loss, increased heating expenses, and potential condensation issues. If you reside in a listed conservation or building area, you may be obliged to retain your current window frames and opt for retrofitting double glazing onto the original wooden frames.
